MySQL order by two fields, cluster fields

Question

I've been wondering how to order rows chronologically, but also keep rows with extra flag together.

Specifically, I have table with orders

Data:

| created     | customer | ...
| 2020-01-01  | xyz      | ...
| 2020-01-10  | abc      | ...
| 2020-01-12  | xyz      | ...
| 2020-01-15  | xyz      | ...
| 2020-01-19  | abc      | ...
| 2020-01-20  | abc      | ...

Desired result:

| created     | customer | ...
| 2020-01-01  | xyz      | ...
| 2020-01-12  | xyz      | ...
| 2020-01-15  | xyz      | ...
| 2020-01-10  | abc      | ...
| 2020-01-19  | abc      | ...
| 2020-01-20  | abc      | ...

So pretty much I need "ORDER BY customers, created", but "customers" need to be ordered by their oldest order.

I hope it makes sense. And thanks in advance for your help.

Answer 1

select * from orders order by customer desc, created_date asc;

2020-01-01  xyz 
2020-01-12  xyz 
2020-01-15  xyz 
2020-01-10  abc 
2020-01-19  abc 
2020-01-20  abc 

Answer 2

You can use window functions in the order by . So:

select t.*
from t
order by min(created) over (partition by customer),
         customer,
         created;

Note that customer is included after the minimum of the creation date. This ensures that if two customers have the same creation date, their data is not all mixed together.

Answer 3

You can try this

select * from tablename
group by customer desc, created asc

Answer 4

Join a query that returns the oldest order of each customer and sort the table first by that oldest date:

select o.*
from orders o 
inner join (
  select customer, min(created) created
  from orders
  group by customer
) c on c.customer = o.customer
order by c.created, o.customer, o.created

See the demo .
Results:

| created    | customer |
| ---------- | -------- |
| 2020-01-01 | xyz      |
| 2020-01-12 | xyz      |
| 2020-01-15 | xyz      |
| 2020-01-10 | abc      |
| 2020-01-19 | abc      |
| 2020-01-20 | abc      |